Color stabilization processing

ABSTRACT

THE USE OF CARBONYL-BISULFITE ADDUCTS, E.G., FORMALDEHYDE BISULFITE, IN COLOR STABILIZATION PROCESSES WHICH INVOLVE TREATING AN IMAGEWISE EXPOSED, INCORPORATED COUPLER, MULTILAYER, SILVER HALIDE SENSITIZED PHOTGRAPHIC ELEMENT IN A DEVELOPER TO FORM SILVER AND COLOR IMAGES AND THEN TREATING THE DEVELOPED ELEMENT WITH A THIOSULFATE STABLILIZER TO STABILIZE THE NONDEVELPED SILVER, PREVENTS OBJECTIONABLE STAIN WHCIH OTHERWISE RESULTS IN BACKGROUDN AREAS. THE CARBONYL-BISULFITE ADDUCT IS DESIRABLY INCORPORATED INTO A THIOSULFATE STABILIZER COMPOSITION.

United States Patent 3,667,952 COLOR STABILIZATION PROCESSING Henry J. Fassbender, Rochester, N.Y., assignor to Eastman Kodak Company, Rochester, N.Y. No Drawing. Filed Oct. 6, 1969, Ser. No. 864,177 Int. Cl. G03c 5/38, 7/30 US. CI. 96-61 5 Claims ABSTRACT OF THE DISCLOSURE This invention relates to stabilization processing of silver halide sensitized color photographic elements. In one of its aspects this invention relates to methods of stabilization processing of imagewise exposed, incorporated coupler, multilayer, silver halide sensitized photographic elements. In another of its aspects this invention relates to methods for color stabilization processing of imagewise exposed, incorporated coupler, silver halide sensitized photo graphic elements which methods include developing color and silver images in alkaline color developer solutions and then stabilizing the undeveloped silver with solutions containing thiosulfate ions.

Rapid photographic processing methods have long been sought in this age of mushrooming technology. The avail ability of a stable print for visual observation a very short time after exposure is not only a convenience but can be an important factor in the success of a project, for example, in industries relying on oscillo graphic recording. Rapid access processing using stabilization methods has provided a means for obtaining quick readable prints. For example, black-and-white silver halide sensitized recording papers have successfully been processed to stable images using stabilizer compositions containing stabilizing agents such as alkali metal and ammonium thiosulfates and thiocyanates, thiourea, thioglycolic acid, etc., as disclosed in Broughton et al. US. Pat. No. 2,614,927. Black-and-white recording materials, however, have limited information storage capacity and present difficulty with apparatus for recording more than one signal at a time because when the signals cross, distinguishing the recorded images becomes ditlicult and sometimes impossible.

To obviate this problem multilayer, color materials, for example, as described in Bodmer et al. US. Pat. No. 3,265,503, have advantageously been utilized. Although such products have enjoyed some success, a limiting factor in the commercial acceptance of the product has been the cost of color stabilization processing materials. Thiocyanate stabilizing agents which have been successfully employed in color stabilization have a somewhat limited capacity. It is thus necessary to discard the stabilizer after use for a relatively short period of time and start with fresh stabilizer. Also, thiocyanate stabilizing agents normally tend to increase tackiness of the resultant stabilized print. Thiosulfate stabilizing agents on the other hand, when used with incorporated coupler, multilayer, silver halide sensitized photographic elements have a tendency to cause stain in the background areas of the stabilized element. The stain appears shortly after processing and turns the normally white background to a yellow to brownish objectionable color thus making the resultant image more diflicult to see. This stain increases with the extent of use of the stabilizer and the capacity of the stabilizer is thereby limited. This stain has been a limiting factor in the acceptability of thiosulfate compositions for color stabilizing processes.

According to the present invention I have found that the stain normally associated with thiosulfate stabilization of developed, incorporated coupler, multilayer, silver halide sensitized photographic elements can be substantially avoided by contacting the element after development with a solution containing carbonyl-bisulfite adducts. There are thus provided methods which employ stabilization baths having high capacity and which can readily be stored as solution concentrates for dilution by the trade.

The carbonyl-bisulfite can be used before and/or after the stabilization bath but according to one advantageous embodiment of the invention it is incorporated in the stabilization composition itself. Accordingly, the stabilization bath contains the dissolved residues from a carbonylbisulfite adduct and thiosulfate. The process according to the present invention involves stabilizing an imagewise eX- posed, incorporated coupler, multilayer, silver halide sensitized photographic element by normal steps comprising developing silver and color images in areas receiving exposure by treating the element with an alkaline developer solution containing p-phenylenediamine color developing agent, and stabilizing the noneXposed ionic silver (silver halide) by complexing the ionic silver with a solution containing thiosulfate ions, but includes the improvement comprising contacting the element after development with a solution containing a carbonyl-bisulfite adduct. The solution containing the carbonyl-bisulfite adduct is advantageously a stabilizing solution, containing thiosulfate ions.

One common processing system employs a four-bath processing cycle. The first two baths normally contain alkali with at least the second bath including p-phenylenediamine color developing agent. The last two baths normally contain thiosul-fate stabilization compositions. The carbonyl-bisulfite adduct according to an especially advantageous embodiment of the present invention is incorporated into at least the last stabilization bath. The method thus advantageously involves developing silver and color images in areas receiving exposure by treating the element with an alkaline developer solution containing color developing agent, then treating the element with a first stabilization solution containing thiosulfate ions, and then treating the element in a second stabilization solution containing thiosulfate ions, the improvement wherein the second stabilization solution contains a carbonyl-bisulfite adduct.

The carbonyl-bisulfite adduct can be formed in situ by the addition of a suitable carbonyl compound, such as low molecular weight aldehydes and ketones, and bisulfite to the aqueous solution or can be added as preformed material which is commercially available, e.g., as sodium formaldehyde bisulfite. The carbonyl moiety is advantageously a simple, low molecular weight aldehyde, such as in acetaldehydeor formaldehyde-bisulfite, or ketone, such as in acetone-bisulfite, but can be selected from those adducts which can be depicted by the general formula RCOR'-bisulfite wherein R and R are independently selected from the class consisting of hydrogen; lower alkyl, e.g., methyl, ethyl, etc.; or substituted alkyl, e.g., as in glutaraldehyde. The bisulfite moiety is advantageously provided as an ammonium or alkali metal bisulfite, e.g., sodium, as in sodium formaldehyde-bisulfite. Thus, the carbonyl-bisulfite is advantageously incorporated into the solution as an ammonium or alkali metal carbonyl-bisulfite. It will be recognized, of course, that the incorporation of such materials into solution will result in dissolved residues of the adduct which will comprise cations (e.g., the alkali metal or ammonium ions), some dissolved free carbonyl compound, free bisulfite, some suliite, as well as some associated carbonyl-bisulfite adduct as would be the case if similar amounts of the bisulfite and carbonyl compound were added separately to the solution for in situ association of the adduct. The concentration of these dissolved residues in the solution may vary with the particular carbonyl-bisulfite chosen, the amount of thiosulfate present, etc., with the maximum determined by solubility of the selected material. The residues are advantageously present at least in an amount equal to that which would be provided by about 20 gm., desirably about 35 gm. to about 300 gm., and especially about 60 gm. to about 100 gm., sodium formaldehyde-bisulfate per liter of solution.

The concentration of thiosulfate ions present in the solution with the carbonyl-bisulfite adduct can also vary widely. It is advantageous to include at least 50 gm. thiosulfate (e.g., as about 132 gm. sodium thiosulfate pentahydrate) per liter of solution. It is usually desirable to include between about 50 gm. to about 400 gm. and especially between about 50 gm. and about 150 gm. per liter of solution. The thiosulfates are usually supplied to the solution as ammonium or alkali metal thiosulfates.

In addition to the thiosulfate, other salts (which can be inert filler) are advantageously included in the final solution to maximize the total salt concentration. This facilitates rapid drying of the stabilized elements. For example, normally an amount of sodium bisulfite is added to the solution in addition to that needed for the carbonylbisulfite adduct. Also, desirably incorporated into the solution are borate ions, hydroxide to adjust the pH to below about 7 and desirably between about and about 6, acetate ions, etc. The temperature of the various baths also can vary, e.g., from about room temperature (70 F.) to about 130 F. with about 100 F. being highly satisfactory.

The photographic elements processed in accordance with the present invention are advantageously incorporated coupler, silver halide sensitized color photographic elements, that is, multilayer elements as described in Bodmer et al. US. Pat. No. 3,265,503. The developer compositions are those normally employed, i.e., containing phenylenediamine color developing agents such as 4-amino-N-ethyl-N-B-hydroxyethyl-3-methylaniline sulfate,

N-ethyl-B-methanesulfonamidoethyl-3-methyl-4-am1noaniline sulfate,

N-ethyl-fi-methanesulfonamidoethyl-4-aminc-aniline,

Z-amino-5-diethy1aminotoluene hydrochloride,

4-N-ethyl-N-fi-hydroxyethylamino aniline,

4-amino-N-ethyl-N- [fl-methanesulfon amido ethyl] -mtoluidine sesquisulfate monohydrate, etc.

The following examples are intended to illustrate my invention and/or advantages thereof.

EXAMPLE 1 A thiosulfate solution is prepared by combining about 167 gm. sodium thiosulfate pentahydrate, gm. sodium bisulfite, and 33 gm. sodium formaldehyde-bisulfite m a liter of water. The pH of the solution is adjusted to about 5.8 with potassium hydroxide. This solution is used as the fourth bath in color stabilization processing of an exposed photographic paper of the type described 1n Example 1 of Bodmer et a1. U.S. Pat. No. 3,265,503 in a CEC 23-109 Oscillogram Processor (Consolidated Electrodynamics Corporation, 360 Sierra Madre Villa, Pasadena, Calif.) which involves passing the exposed element through four separate solutions, each having a temperature of about 100 F., at a speed such that each portion of the paper is in contact with each solution for about seconds. The first solution is conventional phosphate buffered developer containing 4-amino-3-methyl-N-ethy1- N-(fi-hydroxyethyD-aniline sulfate as the color developing agent (about 14 gm. per liter). The second solution is a developer of similar composition but less concentrated (color developing agent concentration of about 10 gm./ 1.). The third bath is similar to the fourth (described above) but contains only about 130 gm./l. sodium thiosulfate, and in place of the formaldehyde-bisulfite about 18 gm./l. sodium acetate and has a pH of about 4. The stabilized element is dried and then stored for a period of three weeks at room temperature. There is little stain detectable in the background areas.

EXAMPLE 2 The procedure according to Example 1 is followed except that about 10 gm. per liter boric acid is included 1n the third bath and about 14 gm. are included in the fourth. Similar results are obtained.

EXAMPLE 3 The procedure according to Example 2 is followed except that the sodium formaldehyde-bisulfite is omitted from the fourth bath. After only a few days an objectionable dark brown stain is detectable in the background areas. As the solution is seasoned, the tendency to stain becomes more and more marked.

EXAMPLE 4 The procedure according to Example 2 is followed except that 67 gm./l. sodium formaldehyde-bisulfite is included instead of 33 gm. The resultant solution processes over 250 square feet of paper/l. eifectively with print background areas remarkably free from stain even after storage for several weeks at room temperature.

EXAMPLE 5 A thiosulfate concentrate is prepared by adding 10 gm. sodium bisulfite, 13 gm. boric acid, 167 gm. sodium thiosulfate pentahydrate, about 250 ml. water, and enough potassium hydroxide to adjust the pH to about 5.4 (about 3 ml. of 45% solution). An adduct concentrate is prepared by adding 67 gm. sodium formaldehyde-bisulfite to about ml. of water. The concentrates are stored separately for a period of about three weeks and then the solutions are added to enough water to make one liter of total solution. The combined solution is used in a process according to Example 1 and functions elfectively with little stain produced in the background areas.

The invention has been described in detail with particular reference to preferred embodiments thereof, but it will be understood that variations and modifications can be eifected within the spirit and scope of the invention.

I claim:

1. In a method for color stabilization processing of imagewise exposed, incorporated coupler, multilayer, silver halide sensitized photographic elements, said method comprising:

(a) developing silver and color images in areas receiving exposure by treating the element with an alkaline developer solution containing p-phenylenediamine color developing agent; and

(b) stabilizing the nonexposed ionic silver by complexing the ionic silver with a solution containing thiosulfate ions;

the improvement comprising after step (a) contacting at least the nonimage areas with an acid solution containing thiosulfate ions and then contacting at least the nonimage areas with a second solution less acid than said other solution and containing thiosulfate ions and in addition dissolved residues from an RCOR bisulfite adduct, wherein R and R are independently selected from the class consisting of hydrogen, lower alkyl and substituted lower alkyl groups, said residues being present in at least an amount equal to that which would be provided by about 20 to 300 gm. sodium formaldehyde-bisulfite dissolved in a liter of solution.

2. The invention according to claim 1 and wherein R and R are hydrogen.

3. The invention according to claim 1 and wherein said RCOR'-bisulfite is a formaldehyde-bisulfite adduct and the dissolved residues therefrom are present in an amount equal to that which would be provided by about 60 gm. to about 100 gm. of sodium formaldehyde-bisulfite per liter of solution.

4. The invention according to claim 1 and wherein said solution containing the dissolved residues from RCOR'- bisulfite also contains thiosulfate ions in a concentration of at least about 50 gm. per liter of solution.

5. The invention according to claim 1 and wherein said RCOR'-bisulfite is a formaldehyde-bisulfite adduct, the dissolved residues therefrom are present in an amount which would be provided by about 60 gm. to about 100 gm. of sodium formaldehyde-bisulfite per liter of solution, and the solution containing said residues further contains thiosulfate ions in a concentration of about 50 to about 400 gm. per liter of solution.

References Cited UNITED STATES PATENTS 2,199,580 5/1940 Tucker 96-61 X 2,387,000 10/1945 Alburger 96-61 2,614,927 10/ 1952 Broughton et a1. 9661 3,304,179 2/1967 Field et al. 96-61 3,212,895 10/1965 Barbier et a1. 96--61 3,335,004 8/1967 Wrisley et al. 96-22 3,549,370 12/1970 Sykes et a1. 96-61 X HAROLD ANSHER, Primary Examiner US. Cl. X.R. 9622 

